Method of making molds.



PATENTED JUNE 16, 1908.

F. M. LAWRENCE. METHOD OF MAKING MOLDS.

APPLICATION FILED FEB. 2Q, 1907.

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UNITED STATES FRANKLIN MUZZY LAIYRENUE, OF PORTLAND, MAINE.

PATENT OFFICE.

METHOD OF MAKING MOLDS.

, Specification of Letters Patent.

Patented June 16, 1908.

Application filed February 20, 1907. Serial No. 358,489.

To all/whom it may concern:

Beit known that I, FRANKLIN MUZZY LAW- RENOE, a citizen of theUnitedStates, residing at Portland, in the county of Cumberland andState of Maine, have invented certain new and useful Improvements inMethods of Making Molds, of which the following is a cope impression.

. specification.

, This invention relates to the method of forming molds for metalcastings and parl provide a method which shall be simple and easilypracticed with ordinary block patterns and using ordinary molding sandwith which castings are usually made.

In the ractice of my method, which will be more ully set forth in thefollowing description, molds are produced which are accurate in therelationof their various parts and this accuracyis secured in theordinary clear I have 1 molders sand without the necessity of carving byskilled labor the parts of the mold. In the practice of this method Iemploy a two part wooden flask, the bottom half designated as a nowelbox and the top half as a' cope box. When filled with sand for castingthey are known as nowel and cope.

For the pur ose of-making my invention llustrated and will describe aflask arrangement by which my invention may be practiced.

Throughout the specification and drawings the Various parts are referredto by like reference numerals which indicate the corresponding partsthroughout.

In the drawings Figure 1 shows a block pattern of' a stove panel, Fig.2, primary and secondary nowel from said pattern, Fig. 3, a similar viewshowing primary nowel lined, Fig. 4,.a similar figure showing inaddition a cope rammed from the lined primary nowel, and Fig. 5, thecope and secondary nowel gated forassemblage.

1. are identical nowel boxes and 2 a copc box.

3 is a block pattern of a stove panel. These panels are usuallydecorated in-relief i and are one of the difficult castings in stove ifoundry work to produce satisfactory as the variations in temperature towhich they are I they are produced with practically uniform thicknessthroughout. 'In practicing my method, therefore, in connection with theproduction of such an article,.I proceed as follows: From a blockpattern 8, shown in Fig 1, I ram up twin primary and secondary sandnowels 4 and 5 in identical nowel boxes 1 and 1 Taking the primary nowela in the box 1 I treat the surface of the sand with silicate of soda orsome other agent to harden its surface structure. This treatment mayable manner. I then prepare a pliantand impressionable ductile flexwhich I roll out in the form of a sheet 7 of the thickness de sired inthe casting to he produced. This plastic material is preferably aspecially prepared sedimentary clay. The rimary nowel 4 is then linedwith this flex sheet which is laid on to and lightly touched into thesuface irregularities of the nowel. The

shellac.(as indicated in Fig. "3), or other suitable substance, to whichthe sand c'ope will not adhere when formed therein. In the primary nowelthus lined and-prepared I ram in the cope box 2, which is placed on theramming up the sand cope 6 on the primary sand nowel 4, treated asdescribed and having the interposed ductile flex sheet 7, the said sheetand treated primary nowel will so mutually adapt themselves along thelines of raised or lowered surfaces in the design or pattern as totransmit to the sand cope 6 practically an identical configuration ofthe original pattern uniformly radially decreased by just the amount ofthe casting desired to -be produced. I'then remove the cope 6 thusformed in the primary nowel 4 and provide it with sprue holes 8 whichconnect with gates 9 formed in the sand of the secondary nowel 5. Theparts thus assembled will constitute a mold having interior surfaces ofcorresponding configuration separated by a space uniform throughoutofth'e thickness desired in the castin "be given with a brush, or, inany other suitlined primary nowel is then sprayed withsubjected renderthem liable to crack unless nowel box 1 a sand cope 6. I find that inThe action of the ductile and impressionable flex sheet on the surfaceof the primary nowel and the formation of the sand cope in such a linednowel is of great. importance as only the ordinary skill of theaveragemolder is required and no unusual foundry process or .naterial isnecessary. The ordinary molders sand, when handled and treated as described, Works to complete satisfaction. The sand cope thus prepared andused with the secondary nowel gives a mold of practical uniformitythroughout and one in which the sharpness of the casting is not lost byany intermediate steps of reproduction.

\Yhere a great number of articles are to be made the casting may betaken for a pattern, finished oil, and molded in the usual manner, but,very oftenit is desired to make only a few articles for a small order,in which case it is possibe to save the expense of preparing the castingfor molding because the primary lined nowel, prepared as aboveindicated, may be used for the production of any number of copes and thenumber of nowels may be multiplied correspondingly from the originalblock pattern. Should but one casting be desired for a metal pattern,the primary nowel box may have its contents removed and the secondarysand nowel may be made with it direct from the block pattern. Careshould be taken in securing uniformity in the blocks and centering studsand some equivalent device should be used to bring the parts into properrelation.

What I therefore claim and desire to secure by Letters Patent is: I

1. The method of making molds consisting in preparing from a singleblock pattern a primary and a secondary molding nowel identical in formand structure, in lining the primary nowel with a sheet of plasticmaterial coated to-prevent adhesion by the cope and having the thicknessdesired in the casting, in forming in the primary nowel thus prepared asand cope, and then assembling the cope with the secondary nowel forcasting in the usual manner.

2. The method of making molds consisting in preparing from a singleblock pattern twin primary and second aryidentical sand nowels, inhardening the primary sand nowel, in lining said primary nowel with asheet of plastic material treated as described and having the thicknessdesired in the casting, in forming in the primary nowel thus prepared asand cope, and then assembling the said cope with the secondary nowelfor casting.

3. The method of making molds consisting in preparing from a singleblock pattern twin primary and secondaryidentical sand nowels, inhardening the surface of the primary sand nowel with silicate of soda,in lining said primary nowel with a sheetof plastic material treated asdescribed and having the thickness desired in the casting, in forming inthe primary nowel thus prepared a sand cope, and then assembling thesaid cope with the secondary nowel for casting.

4. The method of'making molds consisting in preparing from a singlepattern a plurality of sand nowels identical in form and structure, inlining one of said nowels with a plastic sheet, and in forming in saidlined sand nowel one or more sand copes.

In testimony whereof, I affix my signature in presence of two witnesses.

FRANKLIN lllUZZY LAWRENCE.

Witnesses:

GEO. H. H. LAWTON, ARTHUR P. HOWARD.

